1. Field of the Invention
The present invention relates to a thin organic light emitting display that can be used in thin devices like mobile phones, personal digital assistants etc, and where UV-rays cannot be transmitted to an organic light emitting diode via a substrate during fabrication or after fabrication, and a method of making where the substrate is not bent or damaged during fabrication and where the time of making is reduced.
2. Description of the Related Art
An organic light emitting diode (OLED) drives a current to fluorescent or phosphorescent organic material, where electrons and holes are combined, causing the OLED to emit light. An OLED displays an image by voltage programming or current programming on, for example, a matrix of n rows and m columns.
A basic OLED includes an anode, an organic thin film layer, and a cathode electrode. As illustrated in FIG. 1, the organic thin film layer can include an emitting layer (EML) that emits light by forming an excitons upon recombination of electrons and holes, an electron transport layer (ETL) that regulates the velocity of the flow of electrons, and a hole transport layer (HTL) that regulates the velocity of the flow of holes, an electron injection layer (EIL) that improves the injection efficiency of electrons can be formed on the electron transport layer, and a hole-injecting layer (HIL) that improves the injection efficiency of holes can be formed on the hole transport layer.
An OLED can be used as a moving picture display of a small or a large size because of advantages such as a wide-viewing angle, high response speed, and self-emission. The OLED consumes little power, and because a back light is not necessary, and can be fabricated lightly in a flat-panel display. The OLED can be fabricated at a low temperature, and because of the simple fabricating process, it can be fabricated at a low price. Recently, along with rapid development of organic thin-film material-related technologies, the OLED is being considered as a growing technology in the flat panel display market.
However, since electronic applications such as mobile phones, a personal digital assistants, a lap-top computers, computer monitors, and televisions are being made slim, there is a need to fabricate OLED to a thickness of less than 1 mm. However, because a protective film technology that can serve as a substitute to encapsulation technology has not been fully developed, it is difficult to make the thickness of an OLED less than 1 mm.
In order to fabricate an OLED to a thickness of less than 1 mm, JP 2005-340182, JP 2005-222930, and JP 2005-22789 describe a method of fabricating a slim OLED by forming each device layer (i.e., a semiconductor layer and an organic light emitting diode) on two glass substrates, attaching glass substrates in such a manner that each device layer faces each other, and then removing the substrate that does not include the device layer by etching or grinding. However, according to this method, the processes of attachment and etching or grinding consumes a lot of time. According to this method, since almost completed glass substrates are attached, glass substrates, semiconductor layers and OLED devices are often damaged or broken, causing production yield to be low, resulting in high production costs. In an alternative approach, a device layer can be formed on the substrate by fabricating the glass substrate to a thickness of less than 1 mm, however such thin glass substrates can easily cause the glass substrate to bend or be damaged when it comes into contact with the fabricating apparatuses. Therefore, what is needed is an improved design for an OLED and an improved method of making the same which results in a thin OLED where production costs are better contained by improving production yield.